In today's technology, the process for constructing a building typically begins with an architect designing a virtual building in a CAD model, which is a virtual jobsite illustration created on a computer. The CAD model is a Computer Aided Drafting file, and can be either a two-dimensional or a three-dimensional virtual jobsite illustration.
The need for construction contractors to tie a CAD model to the physical world has been around for as long as CAD models have existed. In the past, the conventional solutions have involved pre-creating points of interest on the CAD model, and then later translating those points to the physical world. Unfortunately, this approach adds extraneous data and at least one extra step to the process. Contractors must first create the points on relevant geometry and then use the point data for their physical world work.
The first step of creating points on relevant geometry involves a procedure in which the contractor must figure out which points of the architect CAD model belong with a particular physical structure to be constructed on the jobsite. For example, in a “global mode” the user must select an area of the jobsite floor and select the appropriate points in a “create” mode (or function). All of the points in that area will be displayed, and the user must mentally use selectivity to determine and select the correct points for the particular structure that the user wishes to be laid out at that time.
In the conventional systems, many users start with a “point list,” which is a computer file that includes jobsite coordinates of the points of interest that are to be laid out on the jobsite floor. Often, the point list will be a tabulation of such points of interest in the form of a spreadsheet, with the columns of the spreadsheet containing the point designations, the X-coordinates, and the Y-coordinates (in terms of jobsite coordinates, for example). Another format is for the point list data to be exported to a “CSV file” (a comma separated values file), which can be uploaded to a tablet computer.
The point list could be displayed in a graphical format. However, in the conventional systems, such a graphical file merely displays the relative position of the various points of interest to be laid out, without showing any of the floor plan structure.
Therefore, the user who is performing the actual layout work must attempt to correlate any specific point, or set of points, with a particular structure to be worked on “today.” In other words, if the user desires to lay out a specific diagonal wall, then that user must attempt to select the exact points of the graphical “point list” file that correspond to that diagonal wall, without being able to see the floor plan and the points of interest on the same display. This typically requires the user to go back and forth between the point list screen and the architect's virtual jobsite illustration screen, to figure out which precise points belong with a specific structural feature. Most jobsites contain hundreds, if not thousands, of points of interest, so this “back and forth” work is not an easy, or intuitive, task.
After that has occurred, the user will want to actually lay out a particular point of interest, using a “layout mode” (or function). The user would typically zoom in on the tablet computer's display being used to show the CAD model; otherwise the user would not necessarily be able to see the exact point of interest that is being selected, particularly if the geometry of the structure being laid out has any curved surfaces, which would typically cause a large number of points to be displayed that are relatively close to one another on the screen. Zooming in often will be quite necessary to select the correct point.
Unfortunately, once the layout function has occurred, the user must go back to the global mode and zoom back out to see the next portion of the virtual jobsite illustration that will then be selected as a group of points of interest. The correct point must then be selected and then the layout mode (or function) must then be selected so that the user can zoom in and go to the exact correct point that is to be laid out and staked on the jobsite floor.
When using the conventional systems that have been available, the user must go back and forth between a “point create mode” and the “layout mode,” for staking each point of interest. There are several different types of architect and layout stations that can perform these types of conventional functions. For example, there is a device known as the “total station” that includes a laser distance meter and has an automated angle measuring sensor to detect the azimuth that the laser distance meter is being pointed at.
In one of the more basic forms of a total station, two persons are required to perform the layout procedure: the first person operates the total station itself, and a second person walks around on the jobsite floor with a prism pole. The prism pole has a retroreflective mirror that the laser distance meter of the total station aims at, and if it sees the prism pole's reflective mirror, then the total station will receive a portion of the laser light back and determine the distance. Since the total station knows where the point of interest is supposed to be (once the total station has been set up on this jobsite floor), it will automatically aim at the correct azimuth angle and wait for the second person to position the prism pole at the correct azimuth and distance. The second user at the total station can read out the distance and let the first user who's moving the prism pole know when the prism pole has been placed correctly. This is a painstaking task, and always requires two human beings for the layout and staking procedure.
A more advanced device is known as a total tracking station (TTS), which also includes a laser distance meter; in the total tracking station only a single user is needed for the layout procedure. This user walks around the jobsite floor with a prism pole and also has a remote computer with a display, which is in communication with the total tracking station. The total tracking station gives directions to the user walking around with the remote computer and the prism pole to guide that person to the correct azimuth and distance for accurately positioning the prism pole. Once that has been accomplished, the user will have the prism pole positioned at the correct point that is to be staked on the jobsite floor. While the total tracking station is definitely an improvement over a “raw” total station, the single user still has no visual aid to let that user know exactly where the prism pole is to be positioned except for the display on the remote computer. And even at that, the procedure for positioning the prism pole is onerous, in and of itself, although construction workers are used to working with those devices, regardless of how time consuming and painstaking it is to work with them.
Yet another type of total station is now available which has a pointing laser. In this type of system, the user does not need to use a prism pole, but instead the total station will literally aim a laser beam at the correct point of interest on the jobsite floor. This is a real advancement as compared to devices that require a prism pole; however, there still are some shortcomings. The main shortcoming is that, for a point of interest that is some distance from the location of the total station with pointing laser, the circular laser beam will hit the jobsite floor and show a relatively lengthy ellipse. For example, the ellipse could be a laser beam that is about 3 inches long. While it might seem a simple task to find the exact center of that ellipse, in practice, when the jobsite accuracy is to be within an eighth of an inch, being able to see that exact center of the ellipse can be rather difficult. So this advanced total station with pointing laser still leaves something to be desired, especially for points of interest that are many feet away from the location of the total station itself.
Regardless of what type of total station is being used, with the conventional software that uses CAD models, the user must still bounce between the “point create mode” and the “layout mode” for each point of interest. That may not seem to be an onerous task, but the user must still zoom in and zoom out for each point that is going to be staked on the jobsite floor. If nothing else, this procedure is time consuming
To provide a more detailed description of the conventional sequence of operation that uses a total tracking station will now be presented below, as OUTLINE #1.
OUTLINE #1—SEQUENCE OF OPERATION, using a tracking total station (for example, a Spectra Focus 8 reflectorless total station, Model No. HNA33500), with “Field Link” software, sold by Trimble, Inc. of Sunnyvale, Calif.
(1) Begin setup mode, using CREATE FROM MODEL button, on remote controller.
(2) User views the CAD model two-dimensional display on the remote's screen.                (2a) This is a virtual jobsite illustration.        
(3) User selects the POINT CREATE mode.                (3a) User “taps” the screen at a point of interest of the CAD model. Options:                    (3a-1) Intersection of lines            (3a-2) End point of a line            (3a-3) Mid point of a line            (3a-4) Center of a circle or an arc                        (3b) User designates a point with a number, such as “#100” for the first control point.        (3c) User designates a point with a number, such as “#101” for the second control point.        
(4) User selects the SETUP mode.                (4a) Remote controller displays the CAD model (virtual jobsite illustration).        (4b) User “taps” the screen at the first control point (CP1 ).        (4c) User places the prism pole at CP1.        (4d) User “taps” the “measure” function on the screen.        (4e) User “taps” the screen at the second control point (CP2).        (4f) User places the prism pole at CP2.        (4g) User “taps” the “measure” function on the screen.        (4h) User “taps” the “SET” function on the screen.        (4i) The Setup mode is completed.        
(NOTE: The system software is ready to start selecting points to be laid out on the jobsite floor.)
(5) For the first point of interest (“n”): the CREATE FROM MODEL mode is selected.                (5a) User selects the first point, and “taps” the screen (at an intersection, for example).        (5b) The CAD model software creates a “point icon” at this placement, on the screen.        (5c) User “taps” the “CREATE” function on the screen.                    (5c-1) The software gives that point a designation, such as “#102”.                        (5d) User “taps” the “MEASURE” function on the screen.        
(6) The LAYOUT mode is now selected.                (6a) User “taps” the specific point to be laid out.        (6b) The tracking total station keeps track of the prism pole as it is being moved.                    (6b-1) The instantaneous location of the prism pole is display on the screen of the remote controller. The user can see this.            (6b-2) The remote controller also displays an instruction bar on the screen.            (6b-3) The instruction bar gives directions to the user where to move the prism pole.            (6b-4) As the prism pole approaches point #102, a hockey puck symbol is displayed.            (6b-5) Once the display shows a green circle, the prism pole is “on point.”                        (6c) User “taps” the “MEASURE” function on the screen.                    (6c-1) This informs the software that the user is staking this point #102.                        
(7) For the second point of interest (“n+1”): the CREATE FROM MODEL mode is selected.                (7a) User selects the second point, and “taps” the screen (at an end point, for example).        (7b) The CAD model software creates a “point icon” at this placement, on the screen.        (7c) User “taps” the “CREATE” function on the screen.                    (7c-1) The software gives that point a designation, such as “#103”.                        (7d) User “taps” the “MEASURE” function on the screen.        
(8) The LAYOUT mode is now selected.                (8a) User “taps” the specific point to be laid out.        (8b) The tracking total station keeps track of the prism pole as it is being moved.                    (8b-1) The instantaneous location of the prism pole is display on the screen of the remote controller. The user can see this.            (8b-2) The remote controller also displays an instruction bar on the screen.            (8b-3) The instruction bar gives directions to the user where to move the prism pole.            (8b-4) As the prism pole approaches point #103, a hockey puck symbol is displayed.            (8b-5) Once the display shows a green circle, the prism pole is “on point.”                        (8c) User “taps” the “MEASURE” function on the screen.                    (8c-1) This informs the software that the user is staking this point #103.                        
(9) For the “next” point of interest (“n+m”): the CREATE FROM MODEL mode is selected.                (9a) User selects the next point, and “taps” the screen (at a mid-point, for example).        (9b) The CAD model software creates a “point icon” at this placement, on the screen.        (9c) User “taps” the “CREATE” function on the screen.                    (9c-1) The software gives that point a designation, such as “#103+m”.                        (9d) User “taps” the “MEASURE” function on the screen.        
(10) The LAYOUT mode is now selected.                (10a) User “taps” the specific point to be laid out.        (10b) The tracking total station keeps track of the prism pole as it is being moved.                    (10b-1) The instantaneous location of the prism pole is display on the screen of the remote controller. The user can see this.            (10b-2) The remote controller also displays an instruction bar on the screen.            (10b-3) The instruction bar gives directions to the user where to move the prism pole.            (10b-4) As the prism pole approaches point #103+m, a hockey puck symbol is displayed.            (10b-5) Once the display shows a green circle, the prism pole is “on point.”                        (10c) User “taps” the “MEASURE” function on the screen.                    (10c-1) This informs the software that the user is staking this point #103+m.                        
As can be seen from the above OUTLINE #1, the system for laying out points once the setup has been completed requires the user to bounce between the “CREATE FROM MODEL” mode and the “LAYOUT” mode, for each point of interest to be laid out and then staked.